This patent application claims a benefit of priority from Korean Patent Application No. 1999/53294 filed Nov. 27, 1999 and Korean Patent Application No. 1999/64402 filed Dec. 29, 1999 through PCT Application Serial No. PCT/KR00/01364 filed Nov. 27, 2000, the contents of each of which are incorporated herein by reference
The present invention relates to novel 5-pyrimidinecarboxamide derivatives and the pharmaceutical compositions containing said derivatives. More specifically, the present invention relates to novel 5-pyrimidinecarboxamide derivatives and their pharmaceutically acceptable salts represented below in formula 1, which have excellent inhibitory effect on proliferation of hepatitis B virus and of human immunodeficiency virus. The present invention also relates to the process for preparing compounds of formula 1 and to the pharmaceutical compositions containing said derivatives as effective ingredients against viruses. 
Wherein,
R1 is H, hydroxy, straight or branched alkyl group with C1xcx9cC5, straight or branched alkoxy group with C1xcx9cC5, straight or branched hydroxyalkyl group with C2xcx9cC6, dialkylamino group with C2xcx9cC6 straight or branched alkyl group with C2xcx9cC6 substituted with hydroxy or alkoxycarbonyl group with C2xcx9cC5, cycloalkyl group with C3xcx9cC6, or saturated or unsaturated 5 or 6 membered heterocyclic compounds containing 1 to 3 heteroatoms selected from N, O, and S, which may be unsubstituted or substituted with alkyl group of C1xcx9cC3; R1 may or may not contain asymmetrical carbons;
R2 is H or straight or branched alkyl group with C1xcx9cC4;
Or both R1 and R2 consist of 5 or 6 membered saturated heterocyclic ring containing 1xcx9c3 heteroatoms selected from N, O, and S, which is unsubstituted or substituted with straight or branched alkyl group with C1xcx9cC5 or straight or branched hydroxyalkyl group with C2xcx9cC5;
n is an integer between 0 and 4;
R3 is indazol-5-yl, or indazol-6-yl.
Hepatitis B virus (HBV; referred as xe2x80x9cHBVxe2x80x9d hereinafter) causes acute or chronic hepatitis, which may progress to liver cirrhosis and liver cancer. It is estimated that three hundred million people are infected with HBV in the world (Tiollais and Buendia, Sci. Am., 264, 48, 1991). There has been much research about the molecular biological characteristics of HBV and their relationship to liver diseases in order to find ways to prevent and treat hepatitis B. Various vaccines and diagnostic drugs have been developed and much effort is being channeled into research to find treatment for hepatitis B.
HBV genome consists of genes for polymerase (P), surface protein (pre-S1, pre-S2 and S), core protein (pre-C and C), and X protein. Of these proteins expressed from HBV genes, polymerase, surface protein, and core protein are structural proteins and X protein has a regulatory function.
The gene for HBV polymerase comprises 80% of the whole virus genome and produces a protein of 94kD size with 845 amino acids, which has several functions in the replication of virus genome. This polypeptide includes sequences responsible for activities of protein primer, RNA dependent DNA polymerase, DNA dependent DNA polymerase, and RNase H. Kaplan and his coworkers first discovered reverse transcriptase activities of polymerase, which led to much research in replicating mechanism of HBV.
HBV enters liver when antigenic protein on virion surface is recognized by hepatic cell-specific receptor. Inside the liver cell, DNAs are synthesized by HBV polymerase action, attached to short chain to form complete double helix for HBV genome. Completed double helical DNA genome of HBV produces pre-genomic mRNA and mRNAs of core protein, surface protein, and regulatory protein by the action of RNA polymerase. Using these mRNAs, virus proteins are synthesized. Polymerase has an important function in the production of virus genome, forming a structure called replicasome with core protein and pre-genomic mRNA. This process is called encapsidation. Polymerase has repeated units of glutamic acid at the 3xe2x80x2-end with high affinity for nucleic acids, which is responsible for facile encapsidation.
When replicasome is formed, (xe2x88x92) DNA strand is synthesized by reverse transcribing action of HBV polymerase and (+) DNA strand is made through the action of DNA dependent DNA polymerase, which in turn produces pre-genomic mRNAs. The whole process is repeated until the pool of more than 200 to 300 genomes is maintained (Tiollais and Buendia, Scientific American, 264: 48-54, 1991).
Although HBV and HIV are different viruses, the replication mechanisms during their proliferation have some common steps, namely, the reverse transcription of virus RNA to form DNA and the removal of RNA strand from subsequently formed RNA-DNA hybrid.
Recently, nucleoside compounds such as lamivudine and famvir have been reported to be useful inhibitors of HBV proliferation, although they have been originally developed as therapeutics for the treatment of acquired immune deficiency syndrome (AIDS; referred as xe2x80x9cAIDSxe2x80x9d hereinafter) and herpes zoster infection (Gerin, J. L, Hepatology, 14: 198-199, 1991; Lok, A. S. P., J. Viral Hepatitis, 1: 105-124, 1994; Dienstag, J. L. et al., New England Journal of Medicine, 333: 1657-1661, 1995). However, these nucleoside compounds are considered a poor choice for treatment of hepatitis B because of their high cost and side effects such as toxicity, development of resistant virus and recurrence of the disease after stopping treatment. Effort to find therapeutics for hepatitis B among non-nucleoside compounds has been continued and antiviral effects against HBV have been reported for quinolone compounds (EPO563732, EPO563734), iridos compounds (KR 94-1886), and terephthalic amide derivatives (KR 96-72384, KR 97-36589, KR 99-5100). In spite of much effort, however, effective drugs for treating hepatitis B have not been developed yet and therapeutic method mainly depends on symptomatic treatment.
AIDS is a disease inducing dramatic decrease in immune function in the body cells and causing various symptoms of infection rarely seen in normal human beings, which spread to the whole body. Human immunodeficiency virus (HIV; referred as xe2x80x9cHIVxe2x80x9d hereinafter) responsible for AIDS is known to mainly attack helper T cells, which is one of the T cells with regulatory function in the immune system. When helper T cells are infected with HIV virus and undergo necrosis, human immune system cannot function properly. Impairment in immune function subsequently results in fatal infection and development of malignant tumor. Since AIDS patient has been found in USA in 1981 for the first time, the number increased to more than 850,000 patients in 187 countries in 1993 (WHO 1993 report). WHO predicted that 30 to 40 million more people would be infected with HIV by the year 2000 and 10 to 20 million of them would develop the disease.
At the present time, drugs controlling proliferation of HIV have been most widely used for the treatment of AIDS. Of these, Zidovudine, which had been named Azidothymidine previously, is a drug developed in 1987. Didanosine was developed in 1991 as an alternative medicine for AIDS patients when Zidovudine was either ineffective or could not be used due to side effects. In addition, Zalcitabine was approved for concurrent use with Zidovudine in 1992. These drugs alleviate symptoms, slow down progression of the disease in the infected individuals to full-blown AIDS, and somewhat extend life span in the patients. These drugs, however, are not able to cure the patients completely and often develop problems such as resistance and side effects.
In light of these problems, we, inventors of the present invention, tried to develop therapeutics to treat hepatitis B with little chance of toxicity, side effects, and development of resistant viral strains. We found the compounds with excellent antiviral effect against HBV; synthesized novel 5-pyrimidinecarboxamide derivatives represented in formula 1 and completed the invention by showing their dramatic inhibitory effect on proliferation of HIV as well as of HBV.
The present invention provides novel 5-pyrimidinecarboxamide derivatives and the pharmaceutical compositions containing said derivatives. More specifically, the present invention provides 5-pyrimidinecarboxamide derivatives and their pharmaceutically acceptable salts, the process for their preparation and the pharmaceutical compositions containing said derivatives as effective ingredient. 5-pyrimidinecarboxamide derivatives of the present invention inhibit proliferation of hepatitis B virus as well as of human immunodeficiency virus and may be effectively used for prevention and treatment of hepatitis B and AIDS.
In order to accomplish the aforementioned goal, the present invention provides novel 5-pyrimidinecarboxamide derivatives represented below in formula 1 and their pharmaceutically acceptable salts. 
Wherein,
R1 is H, hydroxy, straight or branched alkyl group with C1xcx9cC5, straight or branched alkoxy group with C1xcx9cC5, straight or branched hydroxyalkyl group with C2xcx9cC6, dialkylamino group with C2xcx9cC6, straight or branched alkyl group with C2xcx9cC6 substituted with hydroxy or alkoxycarbonyl group with C2xcx9cC5, cycloalkyl group with C3xcx9cC6, or saturated or unsaturated 5 or 6 membered heterocyclic compounds containing 1 to 3 heteroatoms selected from N, O, and S, which may be unsubstituted or substituted with alkyl group of C1xcx9cC3; R1 may or may not contain asymmetrical carbons;
R2 is H or straight or branched alkyl group with C1xcx9cC4;
Or both R1 and R2 consist of 5 or 6 membered saturated heterocyclic ring containing 1xcx9c3 heteroatoms selected from N, O, and S, which is unsubstituted or substituted with straight or branched alkyl group with C1xcx9cC5 or straight or branched hydroxyalkyl group with C2xcx9cC5;
R3 is indazol-5-yl or indazol-6-yl;
n is an integer between 0 and 4.
When both R1 and R2 are represented as a 5 or 6 membered heterocyclic compounds with 1 to 3 heteroatoms selected from N, O, and S, n equals 0. This heterocyclic ring may be unsubstituted or substituted with straight or branched alkyl group with C1xcx9cC5, straight or branched hydroxyalkyl group with C2xcx9cC5, or hydroxy group;
When R1 in formula 1 contains asymmetrical carbons, they may exist as either R or S optical isomer and the present invention covers both optical isomers and the racemic mixture as well.
Indazol-5-yl and indazol6-yl groups for R3 in the present invention are represented in formula 2 and 3 respectively. 
Compounds of formula 1 in the present invention may be utilized in the form of salts and the acid addition salts prepared by adding pharmaceutically acceptable free acids are useful. Compounds of formula 1 may be changed to the corresponding acid addition salts according to the general practices in this field. Both inorganic and organic acids may be used as free acids in this case. Among inorganic acids, hydrochloric acid, hydrobromic acid, sulfuric acid, and phosphoric acid may be used. Among organic acids, citric acid, acetic acid, lactic acid, tartaric acid, maleic acid, fumaric acid, formic acid, propionic acid, oxalic acid, trifluoroacetic acid, benzoic acid, gluconic acid, methanesulfonic acid, glycolic acid, succinic acid, 4-toluenesulfonic acid, galacturonic acid, embonic acid, glutamic acid and aspartic acid may be used.
Furthermore, the present invention provides a process for preparing 5-pyrimidinecarboxamide derivatives represented below in scheme 1. 
Wherein, R1, R2, R3 and n are as defined in formula 1.
The process of preparing compounds of formula 1 in the present invention comprises two steps as in the following:
1) Preparation of 5-pyrimidinecarboxylic acid ethyl to ester derivatives of formula 6 by reacting 4-chloro-2-methylthio-5-pyrimidinecarboxylic acid ethyl ester of formula 4 with 5-aminoindazole or 6-aminoindazole of formula 5 (5represents compounds of both formula 2and formula 3; referred as formula 5 hereinafter) in a proper solvent under a basic condition at an appropriate temperature (step 1);
2-A) Preparation of 5-pyrimidinecarboxamide derivatives of formula 1 by reacting the compound of formula 6 prepared in step 1 with amine compound of formula 7 in an appropriate solvent at a proper temperature, or
2-B) Preparation of 5-pyrimidinecarboxamide derivatives of formula 1 by first hydrolyzing the compound of formula 6 synthesized in step 1 to form 5-pyrimidinecarboxylic acid derivatives of formula 8, then activating to Vilsmeier intermediate in the presence of N, N-dimethylformamide and SOCl2, and allowing it to react with amine compound of formula 7.
Chemical agents used in scheme 1, namely, 4-chloro-2-methylthio-5-pyrimidinecarboxylic acid ethyl ester of formula 4, 5-aminoindazole or 6-aminoindazole of formula 5, and amine compound of formula 7 are commercially available and may be purchased easily.
The process of preparing compounds of formula 1 is described in more detail in the following.
For the reaction of 4-chloro-2-methylthio-5-pyrimidinecarboxylic acid ethyl ester of formula 4 with 5-aminoindazole or 6-aminoindazole of formula 5 to synthesize 5-pyrimidinecarboxylic acid ethyl ester derivatives of formula 6, organic compound may be used as a base. It is preferable to use tertiary amine such as triethylamine, N,N-diisopropylethylamine, N-methylmorpholine, N-methylpiperidine, 4-dimethylaminopyridine, N,N-dimethylaniline, 2,6-lutidine, pyridine.
Preferable reaction temperature is 20xcx9c40xc2x0 C. and preferable reaction time is 1xcx9c6 hrs.
Preferable is a single solvent or a mixture of solvents selected from alcohol such as methanol and ethanol, chloroform, methylene chloride, and acetonitrile.
Preparation of 5-pyrimidinecarboxamide derivatives of formula 1 by reacting 5-pyrimidinecarboxylic acid ethyl ester derivatives of formula 6 synthesized in step 1 with amine compound of formula 7 may be carried out using one of two methods.
As in step 2-A, an appropriate amine compound of formula 7 may be used to give good yield of 5-pyrimidinecarboxamide derivatives of formula 1 without first going through the hydrolysis of aminoindazole 5-pyrimidinecarboxylic acid ethyl ester of formula 6.
In this case, amine compound of formula 7 is used to introduce substituents R1 and R2 and an appropriate amine may be selected depending on the kind of substituents desired. For amine compound, methanolic ammonia solution, methanolic methylamine solution, aqueous ethylamine solution, isopropylamine, cyclopropylamine, ethanolamine, or propanolamine are used all of which are commercially available.
For a base, organic base such as used in preparing compounds of formula 6 is used preferably in excess amount compared with that of intermediate of formula 7 in order to increase the reaction efficiency.
For a solvent, a single or a mixture of solvents selected from alcohol such as H2O, methanol, ethanol, and isopropanol or chloroform, methylene chloride, and acetonitrile is preferable.
The reaction temperature is preferably 25xcx9c60xc2x0 C. and may depend on the amine compound used.
As for the reaction in step 2-B, alkali compound used for hydrolyzing the compound of formula 6 is preferably sodium hydroxide, potassium hydroxide, sodium carbonate, or potassium carbonate. 5-Pyrimidinecarboxylic acid derivatives are formed almost quantitatively in the hydrolysis reaction.
For a solvent in this reaction, a mixture of water and alcohol such as methanol or ethanol is preferably used.
Preferable reaction temperature and time are 30xcx9c60xc2x0 C. and 0.5xcx9c3 hrs.
5-pyrimidinecarboxylic acid derivatives are activated using Vilsmeier reagent formed by heating N,N-dimethylformamide and thionyl chloride at 30xcx9c50xc2x0 C. and used in the reaction with an appropriate amine compound of formula 7 at 0xcx9c20xc2x0 C. to prepare 5-pyrimidinecarboxamide derivatives of formula 1, target compound of the present invention.
For a solvent in this reaction, aprotic solvent is preferable such as chloroform, methylene chloride, acetonitrile, tetrahydrofuran, or ether.
Furthermore, the present invention provides the pharmaceutical compositions of therapeutics containing 5-pyrimidinecarboxamide derivatives and their pharmaceutically acceptable salts of formula 1 as effective ingredients to prevent and treat hepatitis B.
The present invention also provides the pharmaceutical compositions of therapeutics with 5-pyrimidinecarboxamide derivatives and their pharmaceutically acceptable salts of formula 1 as effective ingredients to prevent and treat AIDS.
5-pyrimidinecarboxamide derivatives of formula 1 in this invention are effective inhibitors in proliferation of HIV as well as of HBV, since they interfere with removal of RNA strand from RNA-DNA hybrid formed during reverse transcription of viral RNA to DNA which is common in the replication processes for HBV and HIV.
Compounds of formula 1 may be taken orally as well as through other routes in clinical uses; for example, it may be administered intravenously, subcutaneously, intraperitoneally, or locally and used in the form of general drugs.
For the clinical use of drugs with the pharmaceutical compositions of the present invention, compounds of formula 1 may be mixed with pharmaceutically acceptable excipients and made into various pharmaceutically acceptable forms; for example, tablets, capsules, trochise, solutions, suspensions for oral administration; and injection solutions, suspensions, or dried powder to be mixed with distilled water for the formulation of instant injection solution.
Effective dosage for compounds of formula 1 is generally 10xcx9c500 mg/kg, preferably 50xcx9c300 mg/kg for adults, which may be divided into several doses, preferably into 1xcx9c6 doses per day and administered if deemed appropriate by a doctor or a pharmacist.